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Solar eclipse 2012: How to view a solar eclipse

May 20, 2012 | 4:12
pm

How do you watch today's historic solar eclipse? If you're in the continental United States, you'll want to get an elevated, unobstructed view of the western and northwest horizon when the eclipse begins -- as early as the 5 o'clock hour near the northwestern tip of California, local time. Click here for specific times.

The simplest way is to project the eclipse on a surface, so you don't look at the sun directly.

One easy method: using a hand mirror to reflect the light of the sun onto the sidewalk, said Griffith Observatory Director Ed Krupp.

Another idea is to use binoculars to project an image of the sun on a surface, NASA says. Just don't use the binoculars to look at the sun directly!

Another easy way is to crisscross your fingers waffle style to the sunlight, which will project the partial eclipse on the ground in front of you, according to a NASA video on Sunday's eclipse.

If you're near a tree, look underneath the sun-dappled canopy of leaves, and you might be able to see the projections of countless mini-eclipses on the ground.

You can also get a piece of cardboard, punch hole in it with a nail, and then angle the cardboard to project the sun's light on another piece of cardboard. "You'll see a projected image … when the sun goes into eclipse, you'll see a crescent," said Krupp. The smaller the hole, the sharper image you can get.

Don't try to make your own filters to watch the sun directly, the Griffith Observatory says. Tactics such as using multiple sunglasses won't work. Other unsafe methods include using smoked glass, X-rays or photographic film. The only safe filter blocks all but 0.003% of the visible light. A No. 14 welder's glass will work, but those block so much light that most welders don't use them.

And good for you if you've thought far enough in advance to obtain special solar eclipse eyeglasses sold by planetariums and optometrists. Just make sure they're not scratched or damaged.

Children and young adults are most likely of all age groups to suffer from blindness after they look at the sun during a solar eclipse, according to NASA.

"Eclipse blindness" can occur when people look at solar eclipses repeatedly or for a long time without proper protection. It can be temporary or permanent, and it is particularly dangerous because the damage to the eyes happens without any pain, according to B. Ralph Chou, an optometry professor who wrote a report for NASA.

The blindness does not occur "for at least several hours after the damage is done," Chou wrote.

The intense light from the sun, Chou wrote, triggers chemical reactions in the eyes that can damage or destroy the eye cells needed for sight and can cause temporary or permanent blindness.

Also, the bright light and radiation from the sun can cause "heating that literally cooks the exposed tissue" of the eye.

Depending on where you are in the world, Sunday's event will be either a partial or a full "ring of fire" eclipse, in which the moon obscures the whole sun except for a "ring" along its outer edge. It is never safe to look at either type of solar eclipse without proper equipment, Chou wrote.

"Even when 99% of the sun's surface ... is obscured during the partial phases of a solar eclipse, the remaining crescent sun is still intense enough to cause a retinal burn, even though illumination levels are comparable to twilight," Chou said.

A team of eclipse hunters sponsored by Pansonic, broadcasting images atop Mt. Fuji, suffered from disappointing cloud cover atop Japan's highest mountain as the "ring of fire" eclipse began. The crew at the peak was dealing with winds and snow, and all that could be seen were clouds and rain.

"It's just too bad," said one of the men at the top of Mt. Fuji. But Panasonic broadcast impressive images from Wakayama, farther in western Japan.

With NASA's eclipse website beginning to crash under the weight of eclipse frenzy, flat maps of the eclipse path by Jay Anderson, who runs the website Eclipser, are listed below. NASA has linked to Anderson's maps, and Anderson's website credits the eclipse tracks to NASA eclipse expert Fred Espenak. Click the images below or the following links to see a bigger map.